Lapping machine



R. HOFSTETTER LAPPING MACHINE Filed June 27, 1925 April 24, 1928.

3 Sheets- Sheet 2 5 /n ve/vfor R. HOFSTETTER April 24, 1928.

LAPPI NG MACH I NE Filed June 2'7, 1925 3 Sheets-Sheet 3 //7 venfarfloberfflolfsifier by Arfy Y provision of a machine of this characterping two surfaces simultaneouslg Patented Apr. 24, 19 28.

UNITED, STATES- PATENT OFFICE.

ROBERT HORSTE'ITEK OF BERWYN, ILLINOIS,

COMPANY, INCORPORATED, OF NEW YORK, N. Y.,

assmnon T0 wnsrnmr nLnc'rnIc a coaroanmon or mew YORK.

LAPPING MACHINE.

use... filed June 27, 1926. sem No. aaaeo.

Thisinvention relates to lappin or grinding machines, and more articulary to a machine for simultaneous y lapping opposite surfaces of aplurality of articles.

The primary object of this invention is the the lapping surfaces andcarried by a memher which is relatively rapidly revolved and slowlyreciprocated is a work carrying tray.

In order to facilitate the positioning of the,

articles to be lapped prior to the placement of the work carrier betweenthe lapping surfaces, the tray is provided with members which permit thetray to be loaded independent of the lapping machine and during theprocess of lapping other articles. The mechanism for imparting theslowly reciprocating and rapidly rotating motion to the work carriercomprises a gear train which is connected to a source of motive power.The gear train is located just below the lower lapping surface and isprotected from 'abrasive or other deleterious substances by a coverwhich also serves as a clutch plate for imparting motion to the workcarrier along with a housing comprising a plurality of telescopic bafliewalls. When the lapping operation is completed the upper lapping surfaceis moved with respect to the lower lapping surface in a manner such thatmeans is effective for automatically removing any" articles which mayhave adhered to the upper lapping surface. I

Other objects and advantages of the invention will more'fully appearfrom the following detailed description taken in connec- 31 meshing withthree eccentrlc pln gears 32 I tion with the accompanying drawings whichillustrate several embodiments thereof,-.and

in which Fig. 1 is a fragmentary vertical sectional view of one type oflapping machine embodying the features of the invention;

Fig. 2 is a complete plan view thereof upon a reduced scale showing indotted oute0 7 line the position 'of the upper lapping diskwhenreplacing the same or reloading the machine with articles-to belapped;

Fig. 3 is a plan view taken upon the line 3-3 of Fig. 1 showing thesub-plate or tray 66 in position;

Fig. 4 .is a

partly in elevation upon the line 4-4 thereof, and

Fig. 5 1s a fragmentary side view of 21.70

modified form of'the machine.

In the accompanying drawings the machine is shown as adapted to onespecific use, that of lapping or grind faces of carbon and protectorblocks used- "[6 ing opposite surextensively in the art of telephony,but it will be readily understood that the invention can be otherwiseused and embodied.

Referring now to the-drawings in detail and particularly to Fig. 1, at10 is shown the base of the machine upon which is journaled a worm shaft11 which may be connected to any suitable source of power (not shown).The worm shaft 11 is in engagement with a worm wheel '12 keyed to avertically disposed hollow shaft 13. At the lower end of the shaft 13 issecured a suitable combination radial and thrust bearing indicated at 16which is supported in a stationary cap member 17 carried by the base 10.At. its upper end the shaft 13 is radially supported 111 a suitablejournal provided in a gear housing 18 integral with a lap supportingmember 19 secured to the base 10 asindicated at 20.

Within the bore of the hollow shaft 13 is a I fixed shaft 21, the upperend of which is suitably journaled in the shaft 13 and the lower end isprovided with a reduced squared .portion 24 which fits within asimilarly shaped opening 25 formed in a ring 26 secured to thestationarycap member 17 by dowel pins 27. Secured from rotation upon theupper end of the fixed shaft 21 by a pair of Woodrufi keys indicatedat28 and from longitudinal movement thereon by suitable means comprising aspanner wrench screw indicated at 29 is a non-rotatable spur. gear(Figs. 1 and 3) freely rotatable upon studs fragmentary vertical sectionthe u per end of the hollow rotatable shaft 13. pon an enlarged upperend of each of the gears 32 ,is suitably secured a disk 35 having aneccentrically formed raised portion 38. A'combined cover and clutchplate is indicated at 39 for supporting and glving motion to a workcarrier 40 to be fully described hereinafter. Riveted to and dependingfrom the underside of the clutch plate 39 are three pins 41 which. arearranged to freely enter suitable openings formed in the eccentricallydisposed raised portions 38 of the disks 35 carried b the gears 32. Thusit will be seen that w mm the machine is in operation the work carrier40 will be simultaneously. oscillated and rotated so that the articlesbeing lapped will be moved between the lapping surfaces of upper andlower lapping plates 42 and 43 respectively whose opposing parallelfaces constitute the lapplng surfaces.

Referring to Figs. 1, 3 and 4 the top surface of the. plate 39 isprovided with six equally spaced depressions 44 of suitable depth andextending to the periphery of the plate Within which are entered teeth45 s1m1 larly spaced upon the work carrier 40. The work carrier 40comprises a thin plate pro- -vided with a central aperture 46 having theteeth 45 extending inwardly from the wall thereof. Secured to theunderside of each of the teeth 45 by rivets 47 is a plate 48 having thesame contour as the teeth 45 except for a lip portion 49 which extendsbeyond the wall of the aperture 46 as clearly shown in Figs. 3 and 4.The purpose of this lip willbe made apparent hereinafter. a

An im ortant feature of the invention is the provision of a constructionwhichserves to prevent the access of any abraslve ma, terial orparticles from the lapped articles to the driving mechanism for the workcarrier hereinbefore described. This construction consists in thefollowing: V

As described hereinbefore the pins 41 are secured to the clutch plate 39by riveting as clearly shown in Fig. 1 and the plate therei by forms acomplete cover for protecting the actuating mechanism positionedtherebelow from the deleterious effects of abrasives and othersubstances. This is accomplished since no openings or passages occur inthe plate 39 which will permit any abrasive compound thrown upon the topsurface of the plate 39 to seep through and reach the actuatingmechanism. In addition to this cover plate ot er protecting means isprovided as fol lows: Supported above the upper surface of the flange34. of the hollow shaft 13 and the spur ear 31 by three equally spacedpins one of which is indicatedat 53 (Fig. 1) is a hood 54, a dependingcircular wall of which just clears the outside vertical circular wall'of the gear housing 18. Also suitably secured to the underside of theflange 34 is a I Lee-7,600

plate 39 the cooperating hood 54 and ring 55 and the walls 56 and 57respectively and a circular depending wall 63 formed upon the plate 39all abrasive material which in the majority of instances is powderedemery to which water is added durin the lapping operation and the dustresulting from the lapping operation is prevented from ainlug access tothe gears and journals within the gear housing 18. The base 10 isprovided with a cup like formation 64 for the purpose of catching allexcess abrasive material thrown ofl by the machine and which materialmay be readily removed therefrom by first removing a guard ring 65provided with a shouldered lower end which freely fits upon the verticalwall of the cup formation 64. i

The lap plates 42 and 43 are each in the form of a ring preferablycomposed of close grain cast iron and are identical in shape and adaptedto be used interchangeably as the upper onlower lap. The lower lap plate43 rests upon an upper surface 65 of the support 19 and is preventedfrom shifting there- I on by a pin 67 carried by the lap andengaging avertical slot 68 in an upwardly extending flange of the support 19, asclearly shown in Figs. 1 and 3, At one side of the machine is a verticalpost 69 (Fig. 2) supported for rotation upon suitable bearillgs (notshown) provided in the base 10. Adjustably attached to the upper end ofthe post 69 by any suitable means such as set screws is an over-hangingarm or bracket 70 which extends directly over the central 'portion of hebase 10 and at its outer or free end is provided with a vertical opening71. Reciprocally mounted within the opening 71 is a spindle 72 providedwith a gear rack- 73 meshing with a pinion 74 carried by the arm 70 andarranged to be operated by a hand wheel 75 (Fig. 2) whereby the upperlap 42 may be raised from the work for the -purpose of inspection orreloading. Suitable means which may be a ratchet or latch (notnotsufficient a weight may be employed. To

the upper end of the spindle 72 a weight may be secured in any suitablemanner, such acwelght being indicated in dotted outline at upper lap toadjust itself to an slight deviation from parallelism with t e lower lapthat maybe caused by irregularities in the work before the lappingoperation commences. A screw 79 threaded into the end of the spindle 72with a washer intermediate the head of the screw and the spindle servesto retain the spider thereon. The upper surface of the spider isprovided with ratchet teeth 82 which mesh with ratchet teeth provided ona collar 83 reciprocally mounted upon the spindle 72 by a suitable keyand keyway indicated at 84. A compression spring 85 positioned aroundthe spindle between a collar 86 fixed thereto and the collar 83 retainsthe teeth of the latter in mesh with the teeth 82. The purpose of thisratchet clutch will be made apparent hereinafter. Each arm 87 of thespider 78 is adapted at its free end ,by a pair of horizontally disposedpins 88 to support a clamping block 89, the pins 88 being fixed to thearm 87 and adapted to freely enter openings provided in the block. Aremovable pin 90 passing through a lip 91 extending from the arm 87 andinto an opening formed in the block 89 intermediate the pins 88 servesto lock the block to the arm. Formed integral with each block is a'pin94 adapted to enter openings 95 formed in the vertical peripheral wallof the lap plates 42 and 43 when'used as the upper lap, three openings95 being provided in each lappla te. A knob 96 is secured to each blockto facilitate the removal of the block from the arm 87. Thus it will beapparent'tha t a lap plate may be readily released from the spider 78 byfirst removing the pins 90 and then pulling the knobs 96 outwardly. Attimes it is desirable to use the lower lap as the upper one and viceversa. This it will be seen may be readily accomplished. The lap platesare each provided with centralapertures 97 of sumcient size to permitthe reciprocation of the' clutch plate 39 carrying the work carrier 40.

The work carrier 40 referring to Figs. 3 and 4 is provided with aplurality of equally spaced openings 98 each adapted to hold a pluralityof articles which may .be carbon protectorlblocks indicated at 99.

Another important feature of theinvention resides in providing means forfacilitating the mounting of a loaded work carrier in operative positionupon the lower lap, which means also permits an operator while one set vof articles is being lapped 'toreload another work carrier 40 withanother set of articles which upon completion of the lapping of thefirst set and'the removal thereo from the machine may be immediatelymounted in position, thereby reducing the ndn-productlve time of themachine to a minimum. This means comprises asub-plate or tray 104 whichcomprises two identical semi-circular shaped plates 105 which whenbrought together as illustrated in Fig. 3 form a rin of a diameterslightly greater than the wor carrier 40. Fixed to the to surface .ofeach of, and equally spaced therearound are a plurality of retaininglugs 106 each provided with a raised overhanging lip portion 107 clearlyillustrated in Fig. 4. Each plate 105 is rovided with a handle portion109 to facilitate the positioning thereof under the work carrier beforeloading the latter and the withdrawal therefrom upon positioning it fromthe lap plate. To load the work carrier the sub-plate or tray 104 isfirst secured thereunder by gripping the plates 105 by the handleportions 109 and slipping them into posltlon under the carrier until theinner edge of each plate rests upon the lip portion 49..of the plates 48fixed to the carrier with the overhanging lip portion 107 of the witharticles to be lapped and'thereafter the tray '104 may be raised by thehandles 109 and. positioned upon the lowerlap plate 43 with the teeth 45of the carrier entered within the depressions 44 of the clutch plate 39(Figs. 3 and- 4) whereupon the; plates 105 are withdrawn from underthecarrier by simply pulling outwardly in opposite directions upon thehandles 109, the carrier with the artlcles dropping downwardly upon thelap plate 43 as the plates 105 are withdrawn. Upon the completion of alapping opera: tion the upper lap is raised in the manner hereinbeforeexplained by turning the hand wheel and swinging the upper lap to theposition indicated in dotted outline in Fig. 2 thereafter the workcarrier is removed by lifting it upwardly, the articles lapped beingleft upon the lower lap plate 43 and subsequently removed by brushingthem into asuitable receptacle.

Another important feature of the invention is theprovision of meanswhereby any lapped articles adheringto the upper lap plate 105 adjacenttheperip eral edge therello upon completion of the lapping operation(ill articles lap (1 will adhere thereto and if not remove a will notallow the lap plate to .be lowered into proper position upon startinganother lapping operation thereby necessitating the raising of thelapagain and the removal of the articles adherin thereto with a consequentdelay in the comp etion of the lapping operation and output of themachine and frequently damaginga great number of the articles to belapped. To insure the removal of any articles adhering to the upper lapthere is provided a stationary wiper member 110, in the form of a rodsuitably secured to the post 69 (Fig. 2) and projecting at right anglesfrom the normal position of the arm 70 andat such a. level that uponswinging the lap plate 42 to the dotted outline position the lappingsilrface of the plate 42 will just clearthe upper surface of the wiper.In this position the lap plate may be revolved around the wiper 110 'ina clockwise direction due to the ratchet clutch mounted on thespider 78and spindle 72 as hereinbefore described. and any adhering articles willbe brushed from the lap and into a suitable receptacle (not shown).

A modified form of the machine is illustrated in Fig. 5 wherein an aircylinder 111- may be suitably connected to a suitable source of airunder pressure. Suitable control devices (not shown) are provided forraising and lowering the upper lap plate 42 and for applying pressurethereto when the machine is in operation instead of the rack and pinionand weights, respectively, used on the machine first described. Alsoinstead of swinging the upper lap plate'42 horizontally to one side whenremoving'and loading the machine with articles to be lapped ashereinbefore described, the modified machine is provided with powerdriven mechanism for swinging verticallytheupper lap to the dottedoutline position tFig. 5) in which mechanism is also embodied meanswhereby the" lap may be swung horizontally the machine first described.The frame 112 supports a bracket 113 to which is journaled a worm shaft114 meshing with a mutilated worm wheel 115 freely rotatable upon afixed shaft 116 carried by the bracket 113. The shaft 114 may beconnected to any suitable source of power (not shown). Formed upon theworm wheel 115 are two projecting lugs 117 and 118 which serve to limitthe angular movement of the lap plate 42 to 90 or. the movement betweenthe full and dotted outline positions shown (Fig. 5), the lugs engagingeither end of the worm upon the worm shaft 114. Suitably fixed to rotatewith the worm wheel 115 is a bracket 119 provided at its upper end witha circular cup shaped portion 120 within whiclris fitted for rotation adepending flange like portion 121 of an overhangingarm 122 supporting atits free end the air 0 linder 111,' a piston rod 123 operated there ysupporting the upper lap plate 42 by a floating conthe r rotationnection, and for permittin thereof as explained herein efore inconnection with the other type of machine a ratchet clutch 126 isprovided. The arm 122 is normally prevented from rotation upon thebracket 119 by a removable pin 127 passing through an opening providedin a retaining ring 128 fixed to the upper surface of the cup shapedportion 120 and into an opening provided in the flange like portion 121of the arm 122. When it .is desired to swingthe upper lap 42horizontally to one I side the pin 127 is simply removed and the I armmay be readily moved. The ring 128 serves to support' the arm 122 uponthe bracket 119. A wiper member 130 is employed to remove any articlesadhering to the upper lap 42 upon completion of a lapping operation in amanner similar to that described hereinbefore in connection with thefirst described embodiment of the in vention. The member 130 ispositioned The stationary shaft 116 extends outside ofthe bracket 113and has fixed to its end a bevel gear 131 which is in mesh with a secondbevelgear 132 rotatably supported in any suitable manner upon adepending shaft 133 fixed to the cup shaped portion 120 ofthe bracket119. The member 130 is secured for rotation with the gear 132 andit will readily be seen thatupon a movement of the lap 42 to theindicated dotted position thereof that-the bevel gear 132 carried by theshaft 133 and rolling about the fixed bevel gear 131 will cause thewiper member 130 to be moved to the position indicated in dotted outlinewhereupon by revolving the lap 42 through the ratchet clutch 126 anyadhering articles will be brushed from the l rom the foregoingdescription it will be seen that a lappin machine isprovided in whichthe several eatures and arrangement thereof combined provide means bywhich the production of lapped articles may be rapidly and economica lyproduced.

Although the invention has been described with reference to theparticular. construction of machine shown, it is obvious that loo Ill

rier in operative *position'relatir e to said plates comprising asectional ring like mem-' ber adapted to be removed before the lappingoperation 2 The combination of a lapping machine having upper and lowerlapping plates mountable in operative position relative to each other, awork carrier mountable between said plates, means for providing arelative motion between said plates and carrier whereby lappingmovements between the work and plates are accomplished, said carriercomprising a member'in the form of a' ring provided with a plurality ofapertures for positioning articles to be lapped and provided adjacentits' inner, periphery with a plurality of radially projecting lugsspaced from the underside thereof, of means for loading and mounting.said carrier in operative position relative to said plates comprising asectional ring like member arranged to be secured to the carrier at itsinner periphery upon the lugs of the carrier and provided adjacent itsouter periphery with a plurality of inwardly ex-- tending lugs adaptedto engage theupper face of the carrier adjacent its periphery," thesections of said member adapted to be.- removed from the carrier beforethe. lap-' ping operation.

3. In a lapping machine, upperand lower lapping plates mountable inoperative position relative to each other, a work carrier mountablebetween said plates, means" for providing a relative motion betweensaid, plates and carrier whereby lapping movements between the articlesand plates are accomplished, means to elevate and laterally move theupper plate, and means rendered effective upon the I elevation andlateral movement of the upper lapping plate for 3 removing adheringfrom. V

4. In a lapping-machine, upper and lower lapped articles there lappingplates mountable in operative position relative to each other, a workcarrier mountable between said plates, means for providing a relativemotion between said plates and carrier whereby lapping movements betweenthe work and plates are accomplished, means to elevate and laterallymove the upper plate, means associated therewith adapted to permitrotation of said plate, aiid means arranged to remove adhering lappedarticles therefrom upon completion of the lapping operation by causing arotation of said plate upon elevation and lateral movement of the same.

5. In a lapping machine, a' frame, upper and lower lapping platesmountable in operative position relative to each other, a 'work carriermountable between said plates, means for providing a relative motionbetween said plates and carrier whereby lapping movements between thework and plates are accomplished, an arm carried by ,said frame adaptedto swing in a vertical plane for supporting the upper plate, and vmotivefluid operated means for elevating said plate upon the arm and addingpressure thereto when in operative position.

6. In a lapping machine, upper and lower lapping plates mountable inoperative position relative to each other, a work carrier mountablebetween said plates, a gear train positioned below said carrier andplates,

means for connecting said gear train tosaid carrier whereby lappingmovements between the work and plates are accomplished,

said means comprising a plate spanning the gear train and providing aprotecting cover therefor and provided at its peripheral upper edge-withdepressions forming jaws adapted to operatively engage teeth projectingfrom a central aperture/formed in said carrier and means attached to theplate adapted to o'peratively connect with the gear train, said meansbeing attached to the plate in such a manner that noabrasive materialcan 'reach said gear train,

17. In a lapping machine, an upper and lower lapping plate non-rotatablymounted when in lapping position, a work carrier, power driven means,and means "associated with said power driven means for communicating tosaid work carrier. reciprocatory and rotary motion, including asupporting member, depending portions integral there- In witnesswhereof, I hereunto subscribe my-name this 19 day of June A. D., 1925.

' ROBERT HOFSTETIER.

